Co-rotating scroll compressor

ABSTRACT

There is provided a co-rotating scroll compressor in which a driving-side scroll member including a spiral wall between facing end plates can be manufacturable at low cost. A driving-side scroll member (70) includes a first driving-side scroll portion (71), a second driving-side scroll portion (72), and a bolt (31). The first driving-side scroll portion (71) includes a first driving-side end plate (71a) and a first driving-side wall (71b), and is driven by a motor (5). The second driving-side scroll portion (72) includes a second driving-side end plate (72a) and a second driving-side wall (72b). The bolt (31) performs fixing while a front end in a rotation axis direction of the first driving-side wall (71b) and a front end in the rotation axis direction of the second driving-side wall (72b) face each other.

TECHNICAL FIELD

The present invention relates to a co-rotating scroll compressor.

BACKGROUND ART

A co-rotating scroll compressor has been well-known (refer to PTL 1). The co-rotating scroll compressor includes a driving-side scroll and a driven-side scroll that rotates in synchronization with the driving-side scroll, and causes a drive shaft causing the driving-side scroll to rotate and a driven shaft supporting rotation of the driven-side scroll to rotate in the same direction at the same angular velocity while the driven-shaft is offset by a revolving radius from the drive shaft.

CITATION LIST Patent Literature

[PTL 1] the Publication of Japanese Patent No. 5443132

[PTL 2] Japanese Unexamined Patent Application, Publication No. 2014-13044

SUMMARY OF INVENTION Technical Problem

The co-rotating scroll compressor disclosed in PTL 1 described above includes a driving-side scroll member that includes a spiral wall between facing end plates, and a driven-side scroll member that is sandwiched between the end plates of the driving-side scroll member. To realize such a configuration, in PTL 1, an end plate is not provided on an outer periphery of the driven-side scroll member, and the spiral wall of the driving-side scroll member is inserted into the outer periphery of the driven-side scroll member, and the driven-side scroll member is sandwiched and fixed between the end plates on both sides of the driving-side scroll member (refer to FIG. 3 in PTL 1). At this time, front ends of the spiral wall of the driving-side scroll member are inserted into grooves provided on the respective end plates and are fastened by screws after positioning. Accordingly, it is necessary to make a height of the spiral wall larger by a length of the wall inserted into the grooves, which increases the height of the spiral wall as compared with the height originally necessary. When the height of the spiral wall is increased, processing for the large height by an end mill, etc. becomes necessary, which increases the cost. In addition, it is necessary to provide the grooves on the respective end plates. Therefore, a processing step is necessary to provide the grooves, which further increases the cost.

The present invention is made in consideration of such circumstances, and an object of the present invention is to provide a double rotating scroll member in which the driving-side scroll member including the spiral wall between the facing end plates is manufacturable at low cost.

Further, a scroll portion of the scroll compressor requires a cutting process of forming a shape formed by combining complicated curved lines. Therefore, improvement in processability is desired.

The present invention is made in consideration of such circumstances, and an object of the present invention is to provide a co-rotating scroll compressor in which processability of the scroll portion is improved to reduce the cost.

Further, in the co-rotating scroll compressor disclosed in PTL 1, two scroll members facing each other are fixed to each other to configure the driving-side scroll. A material of each of the scroll members fixed to each other is not specified at all. In accordance with the examinations by the inventors, in a case where the scroll members are made of different materials, deformation is caused by thermal expansion difference when temperature is varied, and stress may be increased and performance of the compressor may be impaired. In addition, at a fixed contact portion between the two scroll members, electrolytic corrosion may be caused by reaction with moisture due to difference in ionization tendency.

The present invention is made in consideration of such circumstances, and an object of the present invention is to provide a co-rotating scroll compressor that makes it possible to prevent stress increase and impairing of compression performance caused by temperature variation.

In the co-rotating scroll compressor disclosed in PTL 1, the compression chambers are provided on respective sides of the end plate of the driven-side scroll member between the driven-side scroll member and the driving-side scroll member. However, pressure difference may occur between the compression chambers on the both sides due to dimension variation, etc. in manufacturing, which may inhibit discharge when the compression chambers on the both sides are joined before discharge of working fluid. Further, thrust load may be applied to the scroll members due to the pressure difference between the compression chambers on both sides.

The present invention is made in consideration of such circumstances, and an object of the present invention is to provide a co-rotating scroll compressor that makes it possible to reduce pressure difference between the compression chambers provided on the respective sides of the end plate of the driven-side scroll member.

Further, as the scroll compressor, a fixed and turning scroll compressor in which one of scrolls is a fixed scroll fixed to a housing and the other scroll is a turning scroll performing revolving movement around the fixed scroll is well-known. In addition, surface treatment is performed in order to prevent seizure of the fixed scroll and the turning scroll (see PTL 2).

A region to be subjected to the surface treatment in a case where the surface treatment is performed on the scroll member of the co-rotating scroll compressor in order to prevent seizure, has not been examined. In particular, if the surface treatment is performed on an unnecessary portion, cost is increased.

The present invention is made in consideration of such circumstances, and an object of the present invention is to provide a co-rotating scroll compressor that makes it possible to hold down the cost of the surface treatment.

Solution to Problem

To solve the above-described issues, a co-rotating scroll compressor according to the present invention adopts the following solutions.

A co-rotating scroll compressor according to an aspect of the present invention includes: a driving-side scroll member that is rotationally driven by a driving unit and includes a spiral driving-side wall disposed on a driving-side end plate; a driven-side scroll member that includes a spiral driven-side wall corresponding to the driving-side wall, the driven-side wall being disposed on a driven-side end plate and engaging with the driving-side wall to form a compression space; and a synchronous driving mechanism that transmits driving force from the driving-side scroll member to the driven-side scroll member to cause the driving-side scroll member and the driven-side scroll member to perform rotational movement in a same direction at a same angular velocity, in which the driving-side scroll member includes a first driving-side scroll portion, a second driving-side scroll portion, and a wall fixing part, the first driving-side scroll portion including a first driving-side end plate and a first driving-side wall and being driven by the driving unit, the second driving-side scroll portion including a second driving-side end plate and a second driving-side wall, and the wall fixing part performing fixing while a front end in a rotation axis direction of the first driving-side wall and a front end in the rotation axis direction of the second driving-side wall face each other, and the driven-side scroll member includes a first driven-side wall and a second driven-side wall, the first driven-side wall being provided on one side surface of the driven-side end plate and engaging with the first driving-side wall, and the second driven-side wall being provided on another side surface of the driven-side end plate and engaging with the second driving-side wall.

The driving-side wall disposed on the driving-side end plate of the driving-side scroll member and the driven-side wall of the driven-side scroll member engage with each other to form the compression space. The driving-side scroll member is rotationally driven by the driving unit, and the driving force transmitted to the driving-side scroll member is transmitted to the driven-side scroll member through the synchronous driving mechanism. As a result, the driven-side scroll member rotates as well as performs rotational movement in the same direction at the same angular velocity with respect to the driving-side scroll member. As described above, the co-rotating scroll compressor in which both of the driving-side scroll member and the driven-side scroll member rotate is provided.

The driving-side scroll member is configured by the first driving-side wall and the second driving-side wall, and the walls of the driving-side scroll member are divided in a height direction. This makes it possible to reduce a processing height when the walls are processed, and to accordingly perform processing with high precision at high speed.

Further, in the co-rotating scroll compressor according to the aspect of the present invention, the wall fixing part includes a key groove provided on each of the front end of the first driving-side wall and the front end of the second driving-side wall, and a key member to be inserted into the key grooves.

The co-rotating scroll compressor includes the wall fixing part that fixes the front ends of the two driving-side walls. In addition, the wall fixing part includes the key groove provided on each of the front end of the first driving-side wall and the front end of the second driving-side wall, and the key member to be inserted into the key grooves. The key grooves are provided along the respective front ends of the walls each formed in the spiral shape. This allows for positioning in not only one direction but also two directions, which makes it possible to precisely assemble the walls.

Further, in the co-rotating scroll compressor according to the aspect of the present invention, the wall fixing part includes a groove provided on one of the front end of the first driving-side wall and the front end of the second driving-side wall, and a protrusion that is provided on the other of the front end of the second driving-side wall and the front end of the first driving-side wall and is to be inserted into the groove.

The co-rotating scroll compressor includes the wall fixing part that fixes the front ends of the two driving-side walls. In addition, the wall fixing part includes the groove provided on one of the front end of the first driving-side wall and the front end of the second driving-side wall, and the protrusion that is provided on the other of the front end of the second driving-side wall and the front end of the first driving-side wall and is to be inserted into the groove. The groove and the protrusion are provided along the respective front ends of the walls each formed in the spiral shape. This allows for positioning in not only one direction but also two directions, which makes it possible to precisely assemble the walls.

A co-rotating scroll compressor according to an aspect of the present invention includes: a driving-side scroll member that is rotationally driven by a driving unit and includes a plurality of spiral driving-side walls disposed at predetermined angular intervals around a center of a driving-side end plate; a driven-side scroll member that includes spiral driven-side walls in a number corresponding to the number of driving-side walls, the driven-side walls being provided at predetermined angular intervals around a center of a driven-side end plate and engaging with the respective driving-side walls to form compression spaces; and a synchronous driving mechanism that transmits driving force from the driving-side scroll member to the driven-side scroll member to cause the driving-side scroll member and the driven-side scroll member to perform rotational movement in a same direction at a same angular velocity, in which the driving-side scroll member includes a first driving-side scroll portion, a second driving-side scroll portion, and a wall fixing part, the first driving-side scroll portion including a first driving-side end plate and a first driving-side wall and being driven by the driving unit, the second driving-side scroll portion including a second driving-side end plate and a second driving-side wall, and the wall fixing part performing fixing while a front end in a rotation axis direction of the first driving-side wall and a front end in the rotation axis direction of the second driving-side wall face each other, the driven-side scroll member includes a first driven-side scroll portion and a second driven-side scroll portion, the first driven-side scroll portion including a first driven-side end plate and a first driven-side wall that is provided on one side surface of the first driven-side end plate and engages with the first driving-side wall, and the second driven-side scroll portion including a second driven-side end plate and a second driven-side wall that is provided on one side surface of the second driven-side end plate and engages with the second driving-side wall, and the first driven-side end plate and the second driven-side end plate are fixed while another side surface of the first driven-side end plate and another side surface of the second driven-side end plate are superimposed.

Each of the driving-side walls disposed at the predetermined angular intervals around the center of the end plate of the driving-side scroll member and corresponding driven-side wall of the driven-side scroll member engage with each other. As a result, the scroll compressor that includes a plurality of pairs of one driving-side wall and one driven-side wall and includes the walls forming a plurality of lines is configured. The driving-side scroll member is rotationally driven by the driving unit, and the driving force transmitted to the driving-side scroll member is transmitted to the driven-side scroll member through the synchronous driving mechanism. As a result, the driven-side scroll member rotates as well as performs rotational movement in the same direction at the same angular velocity with respect to the driving-side scroll member. As described above, the co-rotating scroll compressor in which both of the driving-side scroll member and the driven-side scroll member rotate is provided.

The first driving-side wall and the first driven-side wall engage with each other to form the compression chamber, and the second driving-side wall and the second driven-side wall engage with each other to form the compression chamber. This forms the compression chambers separated from each other. At this time, the first driving-side scroll portion and the second driving-side scroll portion are provided as members separated from each other. This enhances processability of the driving-side scroll member, which makes it possible to reduce the cost.

Further, as for the driven-side scroll member, the first driven-side end plate and the second driven-side end plate are not shared by one member but are fixed to each other while the other side surfaces of the first driven-side end plate and the second driven-side end plate are superimposed on each other. Accordingly, it is possible to provide the first driven-side scroll portion and the second driven-side scroll portion as members separated from each other. This also enhances processability of the driven-side scroll member, which makes it possible to reduce the cost.

Further, a co-rotating scroll compressor according to an aspect of the present invention includes: a driving-side scroll member that is rotationally driven by a driving unit and includes a plurality of spiral driving-side walls disposed at predetermined angular intervals around a center of a driving-side end plate; a driven-side scroll member that includes spiral driven-side walls in a number corresponding to the number of driving-side walls, the driven-side walls being provided at predetermined angular intervals around a center of a driven-side end plate and engaging with the respective driving-side walls to form compression spaces; and a synchronous driving mechanism that transmits driving force from the driving-side scroll member to the driven-side scroll member to cause the driving-side scroll member and the driven-side scroll member to perform rotational movement in a same direction at a same angular velocity, in which the driving-side scroll member includes a first driving-side scroll portion, a second driving-side scroll portion, and a wall fixing part, the first driving-side scroll portion including a first driving-side end plate and a first driving-side wall and being driven by the driving unit, the second driving-side scroll portion including a second driving-side end plate and a second driving-side wall, and the wall fixing part performing fixing while a front end in a rotation axis direction of the first driving-side wall and a front end in the rotation axis direction of the second driving-side wall face each other, the driven-side scroll member includes a first driven-side wall and a second driven-side wall, the first driven-side wall being provided on one side surface of the driven-side end plate and engaging with the first driving-side wall, and the second driven-side wall being provided on another side surface of the driven-side end plate and engaging with the second driving-side wall, and timing when fluid is compressed and discharged by the first driving-side scroll portion and timing when fluid is compressed and discharged by the second driving-side scroll portion are different from each other.

The timings when the fluid is compressed and discharged by the respective driving-side scroll portions are made different from each other, which makes it possible to suppress pulsation of the fluid discharged from the compressor.

For example, the discharge timings can be made different from each other by changing the shape of each of the walls and the shape of each of the end plates configuring the compression chambers.

A shift amount of the discharge timing is set to one degree or more in a rotation angle of the scroll member, preferably five degrees or more, and more preferably ten degrees or more.

Further, a co-rotating scroll compressor according to an aspect of the present invention includes: a driving-side scroll member that is rotationally driven by a driving unit and includes a plurality of spiral driving-side walls disposed at predetermined angular intervals around a center of a driving-side end plate; a driven-side scroll member that includes spiral driven-side walls in a number corresponding to the number of driving-side walls, the driven-side walls being provided at predetermined angular intervals around a center of a driven-side end plate and engaging with the respective driving-side walls to form compression spaces; and a synchronous driving mechanism that transmits driving force from the driving-side scroll member to the driven-side scroll member to cause the driving-side scroll member and the driven-side scroll member to perform rotational movement in a same direction at a same angular velocity, in which the driving-side scroll member includes a first driving-side scroll portion, a second driving-side scroll portion, and a wall fixing part, the first driving-side scroll portion including a first driving-side end plate and a first driving-side wall and being driven by the driving unit, the second driving-side scroll portion including a second driving-side end plate and a second driving-side wall, and the wall fixing part performing fixing while a front end in a rotation axis direction of the first driving-side wall and a front end in the rotation axis direction of the second driving-side wall face each other, the driven-side scroll member includes a first driven-side wall and a second driven-side wall, the first driven-side wall being provided on one side surface of the driven-side end plate and engaging with the first driving-side wall, and the second driven-side wall being provided on another side surface of the driven-side end plate and engaging with the second driving-side wall, the second driving-side scroll portion includes a discharge port through which fluid compressed by the first driving-side scroll portion as well as fluid compressed by the second driving-side scroll portion are discharged, and discharge pressure of the fluid compressed by the first driving-side scroll portion is set higher than discharge pressure of the fluid compressed by the second driving-side scroll portion.

The discharge pressure of the fluid compressed by the first driving-side scroll portion is set higher than the discharge pressure of the fluid compressed by the second driving-side scroll portion. This makes it possible to smoothly discharge the discharged fluid guided from the first driving-side scroll from the discharge port provided in the second driving-side scroll portion.

For example, the discharge pressure can be adjusted by changing the shape of each of the walls and the shape of each of the end plates configuring the compression chambers.

As the pressure difference between the discharge pressures, a pressure difference that enables the discharged fluid from the first driving-side scroll portion to flow out from the discharge port without being inhibited by the discharged fluid from the second driving-side scroll portion, is sufficient.

Further, a co-rotating scroll compressor according to an aspect of the present invention includes: a driving-side scroll member that is rotationally driven by a driving unit and includes a plurality of spiral driving-side walls disposed at predetermined angular intervals around a center of a driving-side end plate; a driven-side scroll member that includes spiral driven-side walls in a number corresponding to the number of driving-side walls, the driven-side walls being provided at predetermined angular intervals around a center of a driven-side end plate and engaging with the respective driving-side walls to form compression spaces; and a synchronous driving mechanism that transmits driving force from the driving-side scroll member to the driven-side scroll member to cause the driving-side scroll member and the driven-side scroll member to perform rotational movement in a same direction at a same angular velocity, in which the driving-side scroll member includes a first driving-side scroll portion, a second driving-side scroll portion, and a wall fixing part, the first driving-side scroll portion including a first driving-side end plate and a first driving-side wall and being driven by the driving unit, the second driving-side scroll portion including a second driving-side end plate and a second driving-side wall, and the wall fixing part performing fixing while a front end in a rotation axis direction of the first driving-side wall and a front end in the rotation axis direction of the second driving-side wall face each other, the driven-side scroll member includes a first driven-side wall and a second driven-side wall, the first driven-side wall being provided on one side surface of the driven-side end plate and engaging with the first driving-side wall, and the second driven-side wall being provided on another side surface of the driven-side end plate and engaging with the second driving-side wall, and the first driving-side wall has a wall height larger than a wall height of the second driving-side wall.

For example, the first driving-side scroll portion is driven by the driving unit. Thus, the first driving-side scroll portion is designed so as to include rigidity higher than rigidity of the second driving-side scroll portion. As described above, in the case where the first driving-side scroll portion is higher in rigidity than the second driving-side scroll portion, the wall height of the first driving-side wall is made high whereas the wall height of the second driving-side wall is made relatively low. This makes it possible to enhance rigidity of the second driving-side scroll portion.

The wall height is a dimension in the rotation axis direction of the wall disposed on the end plate.

Further, a co-rotating scroll compressor according to an aspect of the present invention includes: a driving-side scroll member that is rotationally driven by a driving unit and includes a plurality of spiral driving-side walls disposed at predetermined angular intervals around a center of a driving-side end plate; a driven-side scroll member that includes spiral driven-side walls in a number corresponding to the number of driving-side walls, the driven-side walls being provided at predetermined angular intervals around a center of a driven-side end plate and engaging with the respective driving-side walls to form compression spaces; and a synchronous driving mechanism that transmits driving force from the driving-side scroll member to the driven-side scroll member to cause the driving-side scroll member and the driven-side scroll member to perform rotational movement in a same direction at a same angular velocity, in which the driving-side scroll member includes a first driving-side scroll portion, a second driving-side scroll portion, and a wall fixing part, the first driving-side scroll portion including a first driving-side end plate and a first driving-side wall and being driven by the driving unit, the second driving-side scroll portion including a second driving-side end plate and a second driving-side wall, and the wall fixing part performing fixing while a front end in a rotation axis direction of the first driving-side wall and a front end in the rotation axis direction of the second driving-side wall face each other, the driven-side scroll member includes a first driven-side wall and a second driven-side wall, the first driven-side wall being provided on one side surface of the driven-side end plate and engaging with the first driving-side wall, and the second driven-side wall being provided on another side surface of the driven-side end plate and engaging with the second driving-side wall, the second driving-side scroll portion includes a discharge port through which fluid compressed by the first driving-side scroll portion as well as fluid compressed by the second driving-side scroll portion are discharged, and the first driving-side wall has a wall height lower than a wall height of the second driving-side wall.

The fluid discharged from the first driving-side scroll portion is discharged from the discharge port of the second driving-side scroll portion. Accordingly, pressure loss occurs when the fluid is guided from the first driving-side scroll portion to the second driving-side scroll portion. Therefore, the wall height of the first driving-side wall is made lower than the wall height of the second driving-side wall. As a result, a flow rate of the fluid compressed by the first driving-side scroll portion is reduced, which makes it possible to reduce pressure loss.

A co-rotating scroll compressor according to an aspect of the present invention includes: a driving-side scroll member that is rotationally driven by a driving unit and includes a spiral driving-side wall disposed on a driving-side end plate; a driven-side scroll member that includes a driven-side wall corresponding to the driving-side wall, the driven-side wall being disposed on a driven-side end plate and engaging with the driving-side wall to form a compression space; and a synchronous driving mechanism that transmits driving force from the driving-side scroll member to the driven-side scroll member to cause the driving-side scroll member and the driven-side scroll member to perform rotational movement in a same direction at a same angular velocity, in which the driving-side scroll member includes a first driving-side scroll portion, a second driving-side scroll portion, and a wall fixing part, the first driving-side scroll portion including a first driving-side end plate and a first driving-side wall and being driven by the driving unit, the second driving-side scroll portion including a second driving-side end plate and a second driving-side wall, and the wall fixing part performing fixing while a front end in a rotation axis direction of the first driving-side wall and a front end in the rotation axis direction of the second driving-side wall face each other, and the driven-side scroll member includes a first driven-side wall and a second driven-side wall, the first driven-side wall being provided on one side surface of the driven-side end plate and engaging with the first driving-side wall, and the second driven-side wall being provided on another side surface of the driven-side end plate and engaging with the second driving-side wall. The co-rotating scroll compressor further includes: a first support member that is fixed to a front end side in the axis direction of the first driven-side wall and rotates together with the first driven-side wall, the first driving-side end plate being disposed in between the first support member and the first driven-side wall; and a second support member that is fixed to a front end side in the axis direction of the second driven-side wall and rotates together with the second driven-side wall, the second driving-side end plate being disposed in between the second support member and the second driven-side wall, in which the first driving-side scroll portion and the second driving-side scroll portion are made of materials having a same linear expansion coefficient, and/or the driven-side scroll member, the first support member, and the second support member are made of materials having a same linear expansion coefficient.

The driving-side wall disposed on the end plate of the driving-side scroll member and the corresponding driven-side wall of the driven-side scroll member engage with each other. The driving-side scroll member is rotationally driven by the driving unit, and the driving force transmitted to the driving-side scroll member is transmitted to the driven-side scroll member through the synchronous driving mechanism. As a result, the driven-side scroll member rotates as well as performs rotational movement in the same direction at the same angular velocity with respect to the driving-side scroll member. As described above, the co-rotating scroll compressor in which both of the driving-side scroll member and the driven-side scroll member rotate is provided.

The first driving-side scroll member and the second driving-side scroll member are fixed to each other. Therefore, there is a possibility that, in a case where temperature is varied, deformation occurs due to thermal expansion difference to increase stress and to adversely affect compression performance. Thus, the first driving-side scroll member and the second driving-side scroll member are made of materials having the same linear expansion coefficient. In addition, the same material is preferably used. When the same material is used, it is possible to prevent electrolytic corrosion from being caused by reaction with moisture due to difference in ionization tendency at fixed contact portions.

The driven-side scroll member, the first support member, and the second support member are fixed to one another. Therefore, there is a possibility that, in a case where temperature is varied, deformation occurs due to thermal expansion difference to increase stress and to adversely affect compression performance. Thus, the driven-side scroll member, the first support member, and the second support member are made of materials having the same linear expansion coefficient. Further, when the same material is used, it is possible to prevent electrolytic corrosion from being caused by reaction with moisture due to difference in ionization tendency at fixed contact portions.

Examples of the used material include an aluminum alloy and a magnesium alloy.

Further, in the co-rotating scroll compressor according to the present invention, the material used for the driven-side scroll member is lower in specific gravity than the materials used for the first driving-side scroll portion and the second driving-side scroll portion.

The both surfaces of the driven-side end plate of the driven-side scroll member face the front end of the first driving-side wall and the front end of the second driving-side wall to form compression chambers. Accordingly, it is difficult to lighten (thin down) the driven-side end plate to reduce the weight. In contrast, in each of the first driving-side end plate and the second driving-side end plate of the driving-side scroll member, only one surface faces the front end of the corresponding driven-side wall, and an opposite surface thereof does not form the compression chamber. Accordingly, the surface not forming the compression chamber can be lightened, in each of the first driving-side end plate and the second driving-side end plate. As a result, it is possible to reduce the weight of the driving-side scroll member.

Accordingly, the material used for the driven-side scroll member that is difficult to be reduced in weight is lower in specific gravity than the materials used for the first driving-side scroll portion and the second driving-side scroll portion, which makes it possible to reduce rotational inertial force.

For example, an aluminum alloy is used for the first driving-side scroll portion and the second driving-side scroll portion, and a magnesium alloy is used for the driven-side scroll member.

A co-rotating scroll compressor according to an aspect of the present invention includes: a driving-side scroll member that is rotationally driven by a driving unit and includes a spiral driving-side wall disposed on a driving-side end plate; a driven-side scroll member that includes a driven-side wall corresponding to the driving-side wall, the driven-side wall being disposed on a driven-side end plate and engaging with the driving-side wall to form a compression chamber; and a synchronous driving mechanism that transmits driving force from the driving-side scroll member to the driven-side scroll member to cause the driving-side scroll member and the driven-side scroll member to perform rotational movement in a same direction at a same angular velocity, in which the driving-side scroll member includes a first driving-side scroll portion, a second driving-side scroll portion, and a wall fixing part, the first driving-side scroll portion including a first driving-side end plate and a first driving-side wall and being driven by the driving unit, the second driving-side scroll portion including a second driving-side end plate and a second driving-side wall, and the wall fixing part performing fixing while a front end in a rotation axis direction of the first driving-side wall and a front end in the rotation axis direction of the second driving-side wall face each other, the driven-side scroll member includes a first driven-side wall and a second driven-side wall, the first driven-side wall being provided on one side surface of the driven-side end plate and engaging with the first driving-side wall, and the second driven-side wall being provided on another side surface of the driven-side end plate and engaging with the second driving-side wall, and the driven-side end plate includes a through hole or a notch in a vicinity of an outer peripheral end of the driven-side wall.

The driving-side wall disposed on the end plate of the driving-side scroll member and the corresponding driven-side wall of the driven-side scroll member engage with each other. The driving-side scroll member is rotationally driven by the driving unit, and the driving force transmitted to the driving-side scroll member is transmitted to the driven-side scroll member through the synchronous driving mechanism. As a result, the driven-side scroll member rotates as well as performs rotational movement in the same direction at the same angular velocity with respect to the driving-side scroll member. As described above, the co-rotating scroll compressor in which both of the driving-side scroll member and the driven-side scroll member rotate is provided.

The through hole or the notch is provided on the driven-side end plate in the vicinity of the outer peripheral end of the driven-side wall. As a result, compression chambers formed on the respective sides of the driven-side end plate communicate with each other to equalize the pressure. This makes it possible to reduce the possibility of inhibiting discharge when the compression chambers on both sides are joined before discharge of the working fluid. Further, it is possible to reduce the possibility of application of a thrust load on the scroll member by the pressure difference between the compression chambers on both sides. Moreover, the through hole or the notch is provided in the vicinity of the outer peripheral end of the driven-side wall to reduce the weight on the outer peripheral side of the driven-side scroll member. This makes it possible to reduce rotational inertial force of the driven-side scroll member.

Further, the through hole or the notch is positioned in the vicinity of the outer peripheral end of the driven-side wall. As a result, the pressure is equalized before the pressure is increased to a predetermined value or more, which makes it possible to reduce recompression.

The vicinity of the outer peripheral end of the driven-side wall indicates for example, in a case where a position of the outer peripheral end is regarded as 0 degrees, a range of ±120 degrees from a center of the spiral wall, preferably ±90 degrees, and more preferably ±45 degrees.

The number of through holes may be one or more.

Further, in the co-rotating scroll compressor according to the aspect of the present invention, the through hole is provided at a position close to a ventral side of the driven-side wall.

Providing the through hole at the position close to the ventral side of the driven-side wall, namely, at a position closer to the ventral side than a dorsal side opposite to the ventral side makes it possible to locate the though hole on the outer peripheral side as close as possible. This makes it possible to further reduce the rotational inertial force of the driven-side scroll member.

A co-rotating scroll compressor according to an aspect of the present invention includes: a driving-side scroll member that is rotationally driven by a driving unit and includes a spiral driving-side wall disposed on a driving-side end plate; a driven-side scroll member that includes a driven-side wall corresponding to the driving-side wall, the driven-side wall being disposed on a driven-side end plate and engaging with the driving-side wall to form a compression chamber; and a synchronous driving mechanism that transmits driving force from the driving-side scroll member to the driven-side scroll member to cause the driving-side scroll member and the driven-side scroll member to perform rotational movement in a same direction at a same angular velocity, in which the driving-side scroll member includes a first driving-side scroll portion, a second driving-side scroll portion, and a wall fixing part, the first driving-side scroll portion including a first driving-side end plate and a first driving-side wall and being driven by the driving unit, the second driving-side scroll portion including a second driving-side end plate and a second driving-side wall, and the wall fixing part performing fixing while a front end in a rotation axis direction of the first driving-side wall and a front end in the rotation axis direction of the second driving-side wall face each other, the driven-side scroll member includes a first driven-side wall and a second driven-side wall, the first driven-side wall being provided on one side surface of the driven-side end plate and engaging with the first driving-side wall, and the second driven-side wall being provided on another side surface of the driven-side end plate and engaging with the second driving-side wall, the driving-side scroll member is not subjected to surface treatment, and at least a region of the driven-side scroll member coming into contact with the driving-side scroll member is subjected to the surface treatment.

The driving-side wall disposed on the end plate of the driving-side scroll member and the corresponding driven-side wall of the driven-side scroll member engage with each other. The driving-side scroll member is rotationally driven by the driving unit, and the driving force transmitted to the driving-side scroll member is transmitted to the driven-side scroll member through the synchronous driving mechanism. As a result, the driven-side scroll member rotates as well as performs rotational movement in the same direction at the same angular velocity with respect to the driving-side scroll member. As described above, the co-rotating scroll compressor in which both of the driving-side scroll member and the driven-side scroll member rotate is provided.

The surface treatment is not performed on the driving-side scroll member, but is performed on at least the region of the driven-side scroll member coming into contact with the driving-side scroll member. As a result, even if the same kind of metal materials are used as a base material of the driving-side scroll member and a base material of the driven-side scroll member, it is possible to prevent seizure. In addition, it is sufficient to perform the surface treatment on one driven-side scroll member without performing the surface treatment on both of the first driving-side scroll portion and the second driving-side scroll portion. This makes it possible to reduce the cost. Accordingly, it is possible to reduce the cost while maintaining durability of the scroll members.

If the surface treatment is performed on both of the first driving-side scroll portion and the second driving-side scroll portion, films formed by the surface treatment on the respective scroll portions may be different in thickness from each other. If the film thicknesses are different from each other, clearances (tip clearances) between the driving-side end plate and the front ends of the driven-side walls are different from one another, which may adversely affect compression performance. In contrast, when the surface treatment is performed on one driven-side scroll member, the surface treatment is performed under the same condition. This makes it possible to make the film thicknesses on both surfaces of the driven-side end plate equivalent to each other, and to accordingly manage the tip clearances with high accuracy.

Note that, as the material of each of the driving-side scroll member and the driven-side scroll member, for example, an aluminum alloy, a magnesium alloy, or an iron-based material is used. For example, electroless nickel-phosphorous (Ni—P) plating is used as the surface treatment.

Further, in the co-rotating scroll compressor according to the aspect of the present invention, a plurality of the driving-side walls are provided at predetermined angular intervals around a center of the driving-side end plate, the driven-side walls in a number corresponding to the number of driving-side walls are provided at predetermined angular intervals around a center of the driven-side end plate, and in the first driven-side walls and/or the second driven-side walls, the surface treatment is not performed on an outer peripheral side in a range from a winding end of each of the first driven-side walls and/or the second driven-side walls to an angle that is obtained by dividing n (rad) by the number of the first driven-side walls or the number of the second driven-side walls.

In the range from the winding end of each of the walls to the angle obtained by dividing n (rad) by the number of walls provided on one surface of the end plate, the outer peripheral side (dorsal side) of each of the walls does not come into contact with the corresponding driving-side wall. Accordingly, it is unnecessary to perform the surface treatment on the angle range, and a tool can be fixed to the angle range in the surface treatment. More specifically, in the surface treatment, the tool is fixed to the angle range to support the driven-side scroll member. As a result, the surface treatment is performable while the driven-side scroll member is stably supported. Note that the range where the surface treatment is not performed is not necessarily provided over the entire angle range described above, and it is sufficient to provide a region where the tool is fixed, as a surface-untreated region.

Further, in the co-rotating scroll compressor according to the aspect of the present invention, a through hole is provided at a center of the driven-side end plate, and the surface treatment is not performed on an inner peripheral surface forming the through hole.

The through hole to discharge the compressed fluid is provided at the center of the driven-side end plate. The driving-side wall does not come into contact with the inner peripheral surface forming the through hole. Accordingly, it is unnecessary to perform the surface treatment on the inner peripheral surface of the through hole, and a tool can be fixed to the inner peripheral surface of the through hole in the surface treatment. More specifically, in the surface treatment, a rod-like tool is inserted into the through hole, and is pressed against and fixed to the inner peripheral surface of the through hole to support the driven-side scroll member. As a result, the surface treatment is performable while the driven-side scroll member is stably supported. Note that the range where the surface treatment is not performed is not necessarily provided over the entire inner peripheral surface of the through hole, and it is sufficient to provide a region where the tool is fixed, as a surface-untreated region.

Advantageous Effects of Invention

The wall of the driving-side scroll member is configured by the first driving-side wall and the second driving-side wall, and the height length of the wall of the driving-side scroll member is divided. This makes it possible to reduce a processing height when the wall is processed, and to accordingly perform processing with high precision at high speed.

As for the driven-side scroll member, the first driven-side end plate and the second driven-side end plate are not shared by one member but are fixed to each other while the other side surfaces of the first driven-side end plate and the second driven-side end plate are superimposed on each other. Accordingly, it is possible to provide the first driven-side scroll portion and the second driven-side scroll portion as members separated from each other. This enhances processability, which makes it possible to reduce the cost.

The driving-side scroll portion, the driven-side scroll portion, and the support members that are fixed to one another are made of the same kind of materials, which makes it possible to prevent stress increase and impairing of compression performance caused by temperature variation.

The hole is provided in the housing to enable access to the driving-side scroll member and the support members. Therefore, it is possible to perform assembling with ease.

The surface treatment is not performed on the driving-side scroll member, but is performed on the driven-side scroll member. This makes it possible to reduce the cost.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a vertical cross-sectional view illustrating a co-rotating scroll compressor according to a first embodiment of the present invention.

FIG. 2 is a perspective view illustrating a first driving-side scroll portion in FIG. 1.

FIG. 3 is a plan view illustrating a second driving-side scroll portion in FIG. 1.

FIG. 4 is a vertical cross-sectional view illustrating a state where positioning is performed by key grooves and a key member.

FIG. 5 is a perspective view illustrating a first driving-side scroll member according to a second embodiment of the present invention.

FIG. 6 is a perspective view illustrating a second driving-side scroll member according to the second embodiment of the present invention.

FIG. 7 is a vertical cross-sectional view illustrating a state where positioning is performed by a groove and a protrusion.

FIG. 8 is a vertical cross-sectional view illustrating a co-rotating scroll compressor according to a third embodiment of the present invention.

FIG. 9 is a plan view illustrating a driving-side scroll member in FIG. 8.

FIG. 10 is a plan view illustrating a driven-side scroll member in FIG. 8.

FIG. 11A is a graph in a case where discharge timings are coincident with each other as Reference Example of pressure variation in a co-rotating scroll compressor according to a fourth embodiment of the present invention.

FIG. 11B is a graph illustrating pressure variation of the co-rotating scroll compressor according to the fourth embodiment of the present invention, in a case where the discharge timings are different from each other.

FIG. 12A is a graph in a case where discharge pressure of second scroll portions is increased as Reference Example of pressure variation of a co-rotating scroll compressor according to a fifth embodiment of the present invention.

FIG. 12B is a graph illustrating pressure variation of the co-rotating scroll compressor according to the fifth embodiment, in a case where discharge pressure of first scroll portions is increased.

FIG. 13A is a vertical cross-sectional view illustrating a main part of the co-rotating scroll compressor corresponding to FIG. 12A.

FIG. 13B is a vertical cross-sectional view illustrating a main part of the co-rotating scroll compressor corresponding to FIG. 12B.

FIG. 14 is a vertical cross-sectional view illustrating a co-rotating scroll compressor according to a sixth embodiment of the present invention.

FIG. 15 is a vertical cross-sectional view illustrating a co-rotating scroll compressor according to a seventh embodiment of the present invention.

FIG. 16 is a vertical cross-sectional view illustrating a co-rotating scroll compressor according to an eighth embodiment of the present invention.

FIG. 17 is a vertical cross-sectional view illustrating a driving-side scroll member in FIG. 16.

FIG. 18 is a vertical cross-sectional view illustrating a driven-side scroll member in FIG. 16.

FIG. 19 is a plan view illustrating the driven-side scroll member illustrated in FIG. 16 according to a ninth embodiment of the present invention.

FIG. 20 is a plan view illustrating a state where the driving-side scroll member and the driven-side scroll member engage with each other.

FIG. 21 is a cross-sectional view as viewed from arrow B in FIG. 20.

FIG. 22 is a plan view illustrating a state where a driving-side scroll member and a driven-side scroll member engage with each other as Reference Example.

FIG. 23 is a cross-sectional view as viewed from arrow C in FIG. 22.

FIG. 24 is a plan view illustrating a modification of the driven-side scroll member.

FIG. 25 is a diagram illustrating a state where two scroll members engage with each other according to a tenth embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS First Embodiment

A first embodiment of the present invention is described below with reference to FIG. 1, etc.

FIG. 1 illustrates a co-rotating scroll compressor 1. The co-rotating scroll compressor 1 can be used as, for example, a supercharger that compresses combustion air (fluid) to be supplied to an internal combustion engine such as a vehicle engine, a compressor that supplies compressed air to an air electrode of a fuel cell, and a compressor that supplies compressed air used in a brake device of a vehicle such as a railway vehicle.

The co-rotating scroll compressor 1 includes a housing 3, a motor (driving unit) 5 accommodated on one end side in the housing 3, and a driving-side scroll member 70 and a driven-side scroll member 90 that are accommodated on the other end side in the housing 3.

The housing 3 has a substantially cylindrical shape, and includes a motor accommodation portion (first housing) 3 a that accommodates the motor 5, and a scroll accommodation portion (second housing) 3 b that accommodates the scroll members 70 and 90.

A cooling fin 3 c to cool the motor 5 is provided on an outer periphery of the motor accommodation portion 3 a. A discharge opening 3 d from which compressed air is discharged is provided at an end part of the scroll accommodation portion 3 b. Note that, although not illustrated in FIG. 1, the housing 3 includes an air suction opening from which air is sucked in.

The scroll accommodation portion 3 b of the housing 3 is divided at a division surface P that is located at a substantially center in an axis direction of the scroll members 70 and 90. The housing 3 includes a flange portion 30 that protrudes outward at a predetermined position in a circumferential direction. A bolt 32 as a fastening means is inserted into and fixed to the flange portion 30, which results in fastening at the division surface P.

The motor 5 is driven by being supplied with power from an unillustrated power supply source. Rotation of the motor 5 is controlled by an instruction from an unillustrated control unit. A stator 5 a of the motor 5 is fixed to an inner periphery of the housing 3. A rotor 5 b of the motor 5 rotates around a driving-side rotation axis CL1. A driving shaft 6 that extends on the driving-side rotation axis CL1 is connected to the rotor 5 b. The driving shaft 6 is connected to a first driving-side shaft portion 7 c of the driving-side scroll member 70.

A rear-end bearing 17 that rotatably supports the driving shaft 6 with the housing 3, is provided at a rear end (right end in FIG. 1) of the driving shaft 6, namely, at an end part of the driving shaft 6 on side opposite to the driving-side scroll member 70.

The driving-side scroll member 70 includes a first driving-side scroll portion 71 on the motor 5 side, and a second driving-side scroll portion 72 on the discharge opening 3 d side.

The first driving-side scroll portion 71 includes a first driving-side end plate 71 a and first driving-side walls 71 b.

The first driving-side end plate 71 a is connected to the first driving-side shaft portion 7 c connected to the driving shaft 6, and extends in a direction orthogonal to the driving-side rotation axis CL1. The first driving-side shaft portion 7 c is provided so as to be rotatable with respect to the housing 3 through a first driving-side bearing 11 that is an angular ball bearing.

The first driving-side end plate 71 a has a substantially disc shape in a planar view. As illustrated in FIG. 2, two first driving-side walls 71 b, namely, two lines of first driving-side walls 71 b each formed in a spiral shape are provided on the first driving-side end plate 71 a. The two lines of first driving-side walls 71 b are disposed at an equal interval around the driving-side rotation axis CL1. Winding end parts 71 e of the respective first driving-side walls 71 b are independent without being fixed to a wall part. In other words, a wall part that connects and reinforces the winding end parts 71 e is not provided. Note that the number of lines of the first driving-side walls 71 b may be one or three or more.

As illustrated in FIG. 1, the second driving-side scroll portion 72 includes a second driving-side end plate 72 a and second driving-side walls 72 b. As illustrated in FIG. 3, two lines of second driving-side walls 72 b are provided similarly to the above-described first driving-side walls 71 b (see FIG. 2). Winding end parts 72 e of the respective second driving-side walls 72 b are independent without being fixed to a wall part. In other words, a wall part that connects and reinforces the winding end parts 72 e is not provided. Note that the number of lines of the second driving-side walls 72 b may be one or three or more.

A second driving-side shaft portion 72 c that extends in the driving-side rotation axis CL1 is connected to the second driving-side end plate 72 a. The second driving-side shaft portion 72 c is provided so as to be rotatable with respect to the housing 3 through a second driving-side bearing 14 that is an angular ball bearing. A preload member 14 a such as a nut and a disc spring is provided on a side of an inner ring of the second driving-side bearing 14. The preload member 14 a is attached to the second driving-side shaft portion 72 c, and is fixed so as to press the inner ring of the second driving-side bearing 14 against the first driving-side bearing 11. As a result, an axial clearance between an expanded shoulder part of the second driving-side shaft portion 72 c and a side surface of the second driving-side bearing 14 is made zero.

The second driving-side shaft portion 72 c includes a discharge port 72 d extending along the driving-side rotation axis CL1.

The first driving-side scroll portion 71 and the second driving-side scroll portion 72 are fixed while front ends (free ends) of the walls 71 b and 72 b corresponding to each other face each other. The walls 71 b and 72 b have the same height.

The first driving-side scroll portion 71 and the second driving-side scroll portion 72 are fixed by bolts (wall fixing parts) 31 that are fastened to respective flange portions 73 provided at a plurality of positions in the circumferential direction. The flange portions 73 are provided so as to protrude outward in a radial direction.

The bolts 31 pass through respective through holes 73 a provided in the flange portions 73 of the first driving-side walls 71 b (see FIG. 2), and are fastened to respective female screw holes 73 b provided in the flange portions 73 of the second driving-side walls 72 b (see FIG. 3).

As illustrated in FIG. 2, key grooves 71 b 1 that each have a fixed width and a fixed depth are provided along the spiral shape on respective front ends of the first driving-side walls 71 b. As illustrated in FIG. 3, key grooves 72 b 1 that each have a fixed width and a fixed depth are also provided along the spiral shape on respective front ends of the second driving-side walls 72 b. These key grooves 71 b 1 and 72 b 1 are provided at such positions that the key grooves 71 b 1 are coincident with the respective key grooves 72 b 1 when the front ends of the walls 71 b are butted to the respective front ends of the walls 72 b.

As illustrated in FIG. 4, a key member 74 is inserted into each pair of the key grooves 71 b 1 and 72 b 1. A key member 74 has a rectangular cross-section, and has a spiral shape in a planar view so as to follow the shapes of the key grooves 71 b 1 and 72 b 1.

Note that the key grooves 71 b 1 and 72 b 2 and the key members 74 are set at positions (angle range) not interfering a driven-side end plate 90 a. Further, the key grooves 71 b 1 and 72 b 1 and the key members 74 may be provided in a plurality of angle ranges.

The driven-side scroll member 90 includes the driven-side end plate 90 a that is provided at a substantially center in the axis direction (horizontal direction in figure). A through hole 90 h is provided at a center of the driven-side end plate 90 a, and causes the compressed air to flow toward the discharge port 72 d.

Driven-side walls 91 b and 92 b are provided on respective sides of the driven-side end plate 90 a. The first driven-side walls 91 b provided on the motor 5 side from the driven-side end plate 90 a engage with the first driving-side walls 71 b of the first driving-side scroll portion 71. The second driven-side walls 92 b provided on the discharge opening 3 d side from the driven-side end plate 90 a engage with the second driving-side walls 72 b of the second driving-side scroll portion 72.

As illustrated in FIG. 3, two first driven-side walls 91 b, namely, two lines of first driven-side walls 91 b are provided. The two lines of driven-side walls 91 b are disposed at an equal interval around a driven-side rotation axis CL2. The second driven-side walls 92 b are also configured in a similar manner. Note that the number of lines of the driven-side walls 91 b and the number of lines of the driven-side walls 92 b may be one or three or more.

A first support member 33 and a second support member 35 are provided at respective ends of the driven-side scroll member 90 in the axis direction (horizontal direction in figure). The first support member 33 is disposed on the motor 5 side, and the second support member 35 is disposed on the discharge opening 3 d side. The first support member 33 is fixed to front ends (free ends) of the respective first driven-side walls 91 b by pins 25 a, and the second support member 35 is fixed to front ends (free ends) of the respective second driven-side walls 92 b by pins 25 b.

A first support member shaft portion 33 a is provided on center axis side of the first support member 33, and the first support member shaft portion 33 a is fixed to the housing 3 through a first support member bearing (first driven-side bearing) 37 that is an angular ball bearing. A second support member shaft portion 35 a is provided on center axis side of the second support member 35, and the second support member shaft portion 35 a is fixed to the housing 3 through a second support member bearing (second driven-side bearing) 38 that is an angular ball bearing. As a result, the driven-side scroll member 90 rotates around the second center axis CL2 through the support members 33 and 35.

A pin-ring mechanism (synchronous driving mechanism) 15 is provided between the first support member 33 and the first driving-side end plate 71 a. More specifically, a ring member 15 a is provided on the first driving-side end plate 71 a, and a pin member 15 b is provided on the first support member 33. The pin-ring mechanism 15 is used as the synchronous driving mechanism that transmits driving force from the driving-side scroll member 70 to the driven-side scroll member 90 such that the both scroll members 70 and 90 synchronously perform revolving movement.

A pin-ring mechanism (synchronous driving mechanism) 15 is provided between the second support member 35 and the second driving-side end plate 72 a. More specifically, a ring member 15 a is provided on the second driving-side end plate 72 a, and a pin member 15 b is provided on the second support member 35. The pin-ring mechanism 15 is used as the synchronous driving mechanism that transmits driving force from the driving-side scroll member 70 to the driven-side scroll member 90 such that the both scroll members 70 and 90 synchronously perform revolving movement.

The co-rotating scroll compressor 1 including the above-described configuration operates in the following manner.

When the driving shaft 6 rotates around the driving-side rotation axis CL1 by the motor 5, the first driving-side shaft portion 7 c connected to the driving shaft 6 also rotates, and the driving-side scroll member 70 accordingly rotates around the driving-side rotation axis CL1. When the driving-side scroll member 70 rotates, the driving force is transmitted from the support members 33 and 35 to the driven-side scroll member 90 through the pin-ring mechanisms 15, and the driven-side scroll member 90 rotates around the driven-side rotation axis CL2. At this time, when the pin members 15 b of the pin-ring mechanisms 15 move while being in contact with the respective ring members 15 a, the both scroll members 70 and 90 relatively perform revolving movement.

When the scroll members 70 and 90 perform revolving movement, the air sucked through the air suction opening of the housing 3 is sucked in from the outer peripheral side of each of the scroll members 70 and 90, and is taken into compression chambers formed by the scroll members 70 and 90. Further, compression is separately performed in compression chambers formed by the first driving-side walls 71 b and the first driven-side walls 91 b and in compression chambers formed by the second driving-side walls 72 b and the second driven-side walls 92 b. A volume of each of the compression chambers is reduced as each of the compression chambers moves toward the center, which compresses the air. The air compressed by the first driving-side walls 71 b and the first driven-side walls 91 b passes through the through hole 90 h provided in the driven-side end plate 90 a, and is joined with the air compressed by the second driving-side walls 72 b and the second driven-side walls 92 b. The resultant air passes through the discharge port 72 d and is discharged to outside from the discharge opening 3 d of the housing 3. The discharged compressed air is guided to an unillustrated internal combustion engine, and is used as combustion air.

The present embodiment achieves the following action effects.

The driving-side scroll member 70 is configured by the first driving-side walls 71 b and the second driving-side walls 72 b, and the height length of the walls 71 b and 72 b of the driving-side scroll member 70 is divided. This makes it possible to reduce a processing height when the walls 71 b and 72 b are processed by, for example, an end mill, and to accordingly perform processing with high precision at high speed.

The front ends of the respective driving-side walls 71 b and 72 b are fixed by the bolts 31. In addition, the key grooves 71 b 1 are provided at the front ends of the first driving-side walls 71 b, the key grooves 72 b 1 are provided at the front ends of the second driving-side walls 72 b, and the key members 74 inserted into the key grooves 71 b 1 and 72 b 1 are provided. The key grooves 71 b 1 and 72 b 1 are provided in the spiral shape along the front ends of the walls 71 b and 72 b provided in the spiral shape. This allows for positioning in not only one direction but also two directions (i.e., positioning in two-dimensional direction along plane in plan view of walls 71 b and 72), which makes it possible to precisely assemble the walls 71 b and 72 b.

Second Embodiment

Next, a second embodiment of the present invention is described with reference to FIG. 5 to FIG. 7.

The present embodiment is different from the first embodiment in that the present embodiment adopts a spigot structure in place of the positioning structure using the key grooves 71 b 1 and 72 b 1 and the key members 74. Accordingly, the common configurations are denoted by the same reference numerals and description thereof is omitted.

As illustrated in FIG. 5, grooves 71 b 2 that each have a fixed width and a fixed depth are provided along the spiral shape on respective front ends of the first driving-side walls 71 b. As illustrated in FIG. 6, protrusions 72 b 2 that each have a fixed width and a fixed height are provided along the spiral shape on respective front ends of the second driving-side walls 72 b. The grooves 71 b 2 and the protrusions 72 b 2 are provided at positions where the grooves 71 b 2 are coincident with the respective protrusions 72 b 2 when the front ends of the walls 71 b are butted to the respective front ends of the walls 72 b.

As illustrated in FIG. 7, the walls 71 b and 72 b are positioned while each of the protrusions 72 b 2 is inserted into and mated with the corresponding groove 71 b 2.

Note that the grooves 71 b 2 and the protrusions 72 b 2 are set at positions (angle range) not interfering the driven-side end plate 90 a. Further, the grooves 71 b 2 and the protrusions 72 b 2 may be provided in a plurality of angle ranges.

The present embodiment achieves the following action effects.

The grooves 71 b 2 are provided at the front ends of the first driving-side walls 71 b, and the protrusions 72 b 2 that are inserted into the respective grooves 71 b 2 is provided at the front ends of the second driving-side walls 72 b. The grooves 71 b 2 and the protrusions 72 b 2 are provided along the front ends of the walls provided in the spiral shape. This allows for positioning in not only one direction but also two directions (i.e., positioning in two-dimensional direction along plane in plan view of walls 71 b and 72 b), which makes it possible to precisely assemble the walls.

Note that the grooves may be provided on the respective second driving-side walls 72 b, and the protrusions may be provided on the respective first driving-side walls 71 b.

Third Embodiment

A third embodiment of the present invention is described below with reference to FIG. 8, etc.

FIG. 8 illustrates a co-rotating scroll compressor 1A. The co-rotating scroll compressor 1A can be used as a supercharger that compresses combustion air (fluid) to be supplied to an internal combustion engine such as a vehicle engine.

The co-rotating scroll compressor 1A includes the housing 3, the motor (driving unit) 5 accommodated on one end side in the housing 3, and the driving-side scroll member 70 and the driven-side scroll member 90 that are accommodated on the other end side in the housing 3.

The housing 3 has a substantially cylindrical shape, and includes the motor accommodation portion 3 a that accommodates the motor 5, and the scroll accommodation portion 3 b that accommodates the scroll members 7 and 9.

The cooling fin 3 c to cool the motor 5 is provided on the outer periphery of the motor accommodation portion 3 a. The discharge opening 3 d from which compressed air is discharged is provided at the end part of the scroll accommodation portion 3 b. Note that, although not illustrated in FIG. 8, the housing 3 includes an air suction opening from which air is sucked in.

The scroll accommodation portion 3 b of the housing 3 is divided at the division surface P that is located at a substantially center part in the axis direction of the scroll members 70 and 70. The housing 3 includes a flange portion (not illustrated) that protrudes outward at a predetermined position in the circumferential direction. A bolt or the like as a fastening means is inserted into and fixed to the flange portion, which results in fastening at the division surface P.

The motor 5 is driven by being supplied with power from an unillustrated power supply source. Rotation of the motor 5 is controlled by an instruction from an unillustrated control unit. The stator 5 a of the motor 5 is fixed to the inner periphery of the housing 3. The rotor 5 b of the motor 5 rotates around the driving-side rotation axis CL1. The driving shaft 6 that extends on the driving-side rotation axis CL1 is connected to the rotor 5 b. The driving shaft 6 is connected to the driving-side driving shaft portion 7 c of the driving-side scroll member 70.

The driving-side scroll member 70 includes the first driving-side scroll portion 71 on the motor 5 side, and the second driving-side scroll portion 72 on the discharge opening 3 d side.

The first driving-side scroll portion 71 includes the first driving-side end plate 71 a and the first driving-side walls 71 b.

The first driving-side end plate 71 a is connected to the driving-side shaft portion 7 c connected to the driving shaft 6, and extends in a direction orthogonal to the driving-side rotation axis CL1. The driving-side shaft portion 7 c is provided so as to be rotatable with respect to the housing 3 through the driving-side bearing 11 that is a ball bearing.

The first driving-side end plate 71 a has a substantially disc shape in a planar view. As illustrated in FIG. 9, three first driving-side walls 71 b, namely, three lines of first driving-side walls 71 b each formed in a spiral shape are provided on the first driving-side end plate 71 a. The three lines of first driving-side walls 71 b are disposed at equal intervals around the driving-side rotation axis CL1. The winding end parts 71 e of the respective first driving-side walls 71 b are independent without being fixed to a wall part. In other words, a wall part that connects and reinforces the winding end parts 71 e is not provided.

As illustrated in FIG. 8, the second driving-side scroll portion 72 includes the second driving-side end plate 72 a and the second driving-side walls 72 b. Three lines of second driving-side walls 72 b are provided similarly to the above-described first driving-side walls 71 b (see FIG. 9).

The second driving-side shaft portion 72 c that extends in the driving-side rotation axis CL1 is connected to the second driving-side end plate 72 a. The second driving-side shaft portion 72 c is provided so as to be rotatable with respect to the housing 3 through the second driving-side bearing 14 that is a ball bearing. The second driving-side shaft portion 72 a includes the discharge port 72 d extending along the driving-side rotation axis CL1.

The first driving-side scroll portion 71 and the second driving-side scroll portion 72 are fixed while the front ends (free ends) of the walls 71 b and 72 b corresponding to each other face each other. The first driving-side scroll portion 71 and the second driving-side scroll portion 72 are fixed by the bolts (wall fixing parts) 31 that are fastened to the respective flange portions 73 provided at a plurality of positions in the circumferential direction. The flange portions 73 are provided so as to protrude outward in the radial direction.

The driven-side scroll member 90 includes a first driven-side scroll portion 91 and a second driven-side scroll portion 92. Driven-side end plates 91 a and 92 a are located at a substantially center of the driven-side scroll member 90 in the axis direction (horizontal direction in figure). The driven-side end plates 91 a and 92 a are fixed while rear surfaces (other side surfaces) of the respective driven-side end plates 91 a and 92 a are superimposed and in contact with each other. Although not illustrated, the fixing is performed by a bolt, a pin, etc. The through hole 90 h is provided at a center of each of the driven-side end plates 91 a and 92 a, and causes the compressed air to flow toward the discharge port 72 d.

The first driven-side walls 91 b are provided on one side surface of the first driven-side end plate 91 a, and the second driven-side walls 92 b are provided on one side surface of the second driven-side end plate 92 a. The first driven-side walls 91 b provided on the motor 5 side from the first driven-side end plate 91 a engage with the first driving-side walls 71 b of the first driving-side scroll portion 71. The second driven-side walls 92 b provided on the discharge opening 3 d side from the second driven-side end plate 92 a engage with the second driving-side walls 72 b of the second driving-side scroll portion 72.

As illustrated in FIG. 10, three first driven-side walls 91 b, namely, three lines of first driven-side walls 91 b are provided. The three lines of driven-side walls 91 b are disposed at equal intervals around the driven-side rotation axis CL2. The support members 33 and 35 described later are fixed to the outer peripheries of the first driven-side walls 91 b. The second driven-side walls 92 b also have the similar configuration.

The first support member 33 and the second support member 35 are provided at the respective ends of the driven-side scroll member 90 in the axis direction (horizontal direction in figure). The first support member 33 is disposed on the motor 5 side, and the second support member 35 is disposed on the discharge opening 3 d side. The first support member 33 is fixed to the front ends (free ends) of the first driven-side walls 91 b, and the second support member 35 is fixed to the front ends (free ends) of the second driven-side walls 92 b. The shaft portion 33 a is provided on the center axis side of the first support member 33, and the shaft portion 33 a is fixed to the housing 3 through the first support member bearing 37. The shaft portion 35 a is provided on the center axis side of the second support member 35, and the shaft portion 35 a is fixed to the housing 3 through the second support member bearing 38. As a result, the driven-side scroll member 90 rotates around the second center axis CL2 through the support members 33 and 35.

The pin-ring mechanism (synchronous driving mechanism) 15 is provided between the first support member 33 and the first driving-side end plate 71 a. More specifically, a circular hole is provided in the first driving-side end plate 71 a, and the pin member 15 b is provided on the first support member 33. The pin-ring mechanism 15 transmits the driving force from the driving-side scroll member 70 to the driven-side scroll member 90, and causes the scroll members 70 and 90 to perform rotational movement in the same direction at the same angular velocity.

The co-rotating scroll compressor 1A including the above-described configuration operates in the following manner.

When the driving shaft 6 rotates around the driving-side rotation axis CL1 by the motor 5, the driving-side shaft portion 7 c connected to the driving shaft 6 also rotates, and the driving-side scroll member 70 accordingly rotates around the driving-side rotation axis CL1. When the driving-side scroll member 70 rotates, the driving force is transmitted from the support members 33 and 35 to the driven-side scroll member 90 through the pin-ring mechanism 15, and the driven-side scroll member 90 rotates around the driven-side rotation axis CL2. At this time, when the pin member 15 b of the pin-ring mechanism 15 moves while being in contact with the inner peripheral surface of the circular hole, the both scroll members 70 and 90 perform rotational movement in the same direction at the same angular velocity.

When the scroll members 70 and 90 perform rotational movement, the air sucked through the air suction opening of the housing 3 is sucked in from outer peripheral side of each of the scroll members 70 and 90, and is taken into the compression chambers formed by the scroll members 70 and 90. Further, compression is separately performed in the compression chambers formed by the first driving-side walls 71 b and the first driven-side walls 91 b and in the compression chambers formed by the second driving-side walls 72 b and the second driven-side walls 92 b. A volume of each of the compression chambers is reduced as each of the compression chambers moves toward the center, which compresses the air. The air compressed by the first driving-side walls 71 b and the first driven-side walls 91 b passes through the through holes 90 h provided in the driven-side end plates 91 a and 92 a, and is joined with the air compressed by the second driving-side walls 72 b and the second driven-side walls 92 b. The resultant air passes through the discharge port 72 d and is discharged to outside from the discharge opening 3 d of the housing 3. The discharged compressed air is guided to an unillustrated internal combustion engine, and is used as combustion air.

The present embodiment achieves the following action effects.

The first driving-side walls 71 b and the first driven-side walls 91 b engage with each other to form the compression chambers, and the second driving-side walls 72 b and the second driven-side walls 92 b engage with each other to form the compression chambers. This forms the compression chambers separated from one another. At this time, the first driving-side scroll portion 71 and the second driving-side scroll portion 72 are provided as members separated from each other. This enhances processability of the driving-side scroll member 70, which makes it possible to reduce the cost.

Further, as for the driven-side scroll member 90, the first driven-side end plate 91 a and the second driven-side end plate 92 a are not shared by one member but are fixed to each other while the rear surfaces of the first driven-side end plate 91 a and the second driven-side end plate 92 a are superimposed on each other. Accordingly, it is possible to provide the first driven-side scroll portion 91 and the second driven-side scroll portion 92 as members separated from each other. This also enhances processability of the driven-side scroll member 90, which makes it possible to reduce the cost.

Fourth Embodiment

Next, a fourth embodiment of the present invention is described with reference to FIG. 11.

In the present embodiment, discharge timing of air compressed by the first scroll portions 71 and 92 and discharge timing of air compressed by the second scroll portions 72 and 92 are different from each other. The other configurations are similar to those in the third embodiment. Therefore, FIG. 8 to FIG. 10 are referred to and description of the configurations is omitted.

The shapes of the first walls 71 b and 72 b are made different from the shapes of the second walls 91 b and 92 b. More specifically, the second walls 91 b and 92 b have shapes shifted from the shapes of the first walls 71 b and 72 b around a center of symmetry of the walls. As a result, timing at which the air is compressed and discharged by the first scroll portions 71 and 91 and timing at which the air is compressed and discharged by the second scroll portions 72 and 92 are different from each other.

More specifically, as illustrated in FIG. 11B, the air compressed by the first scroll portions 71 and 91 shows pressure variation as illustrated by a curved line L1. The air compressed by the second scroll portions 72 and 92 is delayed in pressure variation timing by a predetermined time, and shows pressure variation as illustrated by a curved line L2. At this time, the pressure of air discharged from the discharge port 72 d shows pressure variation as illustrated by a curved line L3 that is obtained by synthesizing the curved line L1 and the curved line L2. Note that a position of pressure P1 in the figure indicates timing when the discharge port 72 d opens.

In contrast, as illustrated in FIG. 11A, in a case where the first walls 71 b and 72 b and the second walls 91 b and 92 b are made in the same shape and pressure is varied at the same timing, the pressure of air discharged from the discharge port 72 d shows pressure variation as illustrated by a curved line L4 that is obtained by synthesizing the curved line L1 and the curved line L2 that shows pressure varied at the same timing. As can be seen from comparison between FIG. 11A and FIG. 11B, the pressure in which the discharge timings have been shifted illustrated in FIG. 11B is low in peak pressure.

Therefore, according to the present embodiment, the timing at which the air is compressed and discharged by the scroll portions 71 and 91 and the timing at which the air is compressed and discharged by the scroll portions 72 and 92 are made different from each other, which makes it possible to suppress pulsation of the air discharged from the compressor 1A.

A shift amount of the discharge timing is set to one degree or more in a rotation angle of the scroll member, preferably five degrees or more, and more preferably ten degrees or more.

Fifth Embodiment

Next, a fifth embodiment of the present invention is described with reference to FIG. 12 and FIG. 13.

In the present embodiment, discharge pressure of the air compressed by the first scroll portions 71 and 92 and discharge pressure of the air compressed by the second scroll portions 72 and 92 are different from each other. The other configurations are similar to those in the third embodiment. Therefore, FIG. 8 to FIG. 10 are referred to and description of the configurations is omitted.

The shapes of the first walls 71 b and 72 b are made different from the shapes of the second walls 91 b and 92 b. More specifically, the number of turns of each of the first walls 71 b and 72 b is made larger than the number of turns of each of the second walls 91 b and 92 b. As a result, discharge pressure of the air compressed by the first scroll portions 71 and 92 is made higher than discharge pressure of the air compressed by the second scroll portions 72 and 92.

More specifically, as illustrated in FIG. 12B, the air compressed by the first scroll portions 71 and 91 (curved line L1) is higher in discharge pressure than the air compressed by the second scroll portions 72 and 92 (curved line L2). When the discharge pressure of the air by the first scroll portions 71 and 91 is made higher than the discharge pressure of the air by the second scroll portions 72 and 92 in the above-described manner, the air flowing out from the first scroll portions 71 and 92 smoothly flows toward the discharge port 72 d after flowing into the second scroll portions 72 and 92, as illustrated in FIG. 13B.

In contrast, in a case where discharge pressure relationship is reversed as illustrated in FIG. 12, namely, in a case where the discharge pressure of the air by the second scroll portions 72 and 92 is higher than the discharge pressure of the air by the first scroll portions 71 and 91, the discharged air flows backward from the second scroll portions 72 and 92 to the first scroll portions 71 and 91 as illustrated in FIG. 13. Therefore, the discharged air from the first scroll portions 71 and 91 cannot smoothly flow toward the discharge port 72 d.

Therefore, according to the present embodiment, the discharge pressure of the air compressed by the first scroll portions 71 and 91 is made higher than the discharge pressure of the air compressed by the second scroll portions 72 and 92, which makes it possible to smoothly discharge the discharged air guided from the first scroll portions 71 and 91 from the discharge port 72 d through the second scroll portions 72 and 92. Note that the discharge pressure may be adjusted by changing the shape of each of the end plates 71 a, 72 a, 91 a, and 92 a that configure the compression chambers.

As the difference between the discharge pressures, a pressure difference that enables the discharged air from the first scroll portions 71 and 91 to flow out from the discharge port 72 d without being inhibited by the discharged air from the second scroll portions 72 and 92, is sufficient.

Sixth Embodiment

Next, a sixth embodiment of the present invention is described with reference to FIG. 14.

A co-rotating scroll compressor 1B according to the present embodiment is different from the third embodiment in terms of a tooth height of each of the first scroll members 71 and 91 and a tooth height of each of the second scroll members 72 and 92. The other configurations are similar to those in the third embodiment. Therefore, the same reference numerals are used, and description of the configurations is omitted.

As illustrated in FIG. 14, a tooth height (wall height) of each of the first walls 71 b and 92 b is made larger than a tooth height of each of the second walls 72 b and 92 b. Accordingly, the positions of the driven-side end plates 91 a and 92 a are shifted toward the discharge opening 3 d from the center of the axial direction position of the scroll members 70 and 90.

In the present embodiment, the pin-ring mechanism 15 is provided on the first driving-side end plate 71 a to transmit the driving force to the driven-side scroll member 90. Therefore, the first driving-side scroll portion 71 is made higher in rigidity than the second driving-side scroll portion 72. Thus, in the case where the first driving-side scroll portion 71 is higher in rigidity than the second driving-side scroll portion 72, the tooth height of each of the first driving-side walls 71 b is made long and the tooth height of each of the second driving-side walls 72 b is made short, which makes it possible to enhance rigidity of the second driving-side scroll portion.

Note that the driven-side end plates 91 a and 92 a illustrated in FIG. 14 are configured by one member; however, the driven-side end plates 91 a and 92 a may be configured by different members as illustrated in FIG. 8.

Seventh Embodiment

Next, a seventh embodiment of the present invention is described with reference to FIG. 15.

A co-rotating scroll compressor 10 according to the present embodiment is different from the third embodiment in terms of a tooth height of each of the first scroll members 71 and 91 and a tooth height of each of the second scroll members 72 and 92. The other configurations are similar to those in the third embodiment. Therefore, the same reference numerals are used, and description of the configurations is omitted.

As illustrated in FIG. 15, a tooth height (wall height) of each of the first walls 71 b and 92 b is made smaller than a tooth height of each of the second walls 72 b and 92 b. Accordingly, the positions of the driven-side end plates 91 a and 92 a are shifted toward the motor 5 from the center of the axial direction position of the scroll members 70 and 90.

The air discharged from the first scroll portions 71 and 91 is discharged from the discharge port 72 d on the second scroll portions 72 and 92 side. Accordingly, pressure loss occurs when the compressed air is guided from the first scroll portions 71 and 91 to the second scroll portions 72 and 92. Therefore, the tooth height of each of the first walls 71 b and 91 b is made smaller than the tooth height of each of the second walls 72 b and 92 b. As a result, a flow rate of the air compressed by the first scroll portions 71 and 91 is reduced, which makes it possible to reduce pressure loss.

Note that the driven-side end plates 91 a and 92 a illustrated in FIG. 14 are configured by one member; however, the driven-side end plates 91 a and 92 a may be configured by different members as illustrated in FIG. 8.

Note that, in the above-described third to seventh embodiments, the pin-ring mechanism 15 is used as the synchronous driving mechanism; however, the present invention is not limited thereto. Alternatively, for example, a crank pin mechanism may be used.

Eighth Embodiment

An eighth embodiment of the present invention is described below with reference to FIG. 16, etc.

FIG. 16 illustrates the co-rotating scroll compressor (scroll compressor) 1. The co-rotating scroll compressor 1 can be used as a supercharger that compresses combustion air (fluid) to be supplied to an internal combustion engine such as a vehicle engine.

The co-rotating scroll compressor 1 includes the housing 3, the motor (driving unit) 5 accommodated on one end side in the housing 3, and the driving-side scroll member 70 and the driven-side scroll member 90 that are accommodated on the other end side in the housing 3.

The housing 3 has a substantially cylindrical shape, and includes the motor accommodation portion 3 a that accommodates the motor 5, and the scroll accommodation portion 3 b that accommodates the scroll members 70 and 90.

The cooling fin 3 c to cool the motor 5 is provided on the outer periphery of the motor accommodation portion 3 a. The discharge opening 3 d from which compressed air (working fluid) is discharged is provided at the end part of the scroll accommodation portion 3 b. Note that, although not illustrated in FIG. 16, the housing 3 includes an air suction opening from which air (working fluid) is sucked in.

The motor 5 is driven by being supplied with power from an unillustrated power supply source. Rotation of the motor 5 is controlled by an instruction from an unillustrated control unit. The stator 5 a of the motor 5 is fixed on the inner periphery of the housing 3. The rotor 5 b of the motor 5 rotates around the driving-side rotation axis CL1. The driving shaft 6 that extends on the driving-side rotation axis CL1 is connected to the rotor 5 b. The driving shaft 6 is connected to the first driving-side shaft portion 7 c of the driving-side scroll member 70.

The driving-side scroll member 70 includes the first driving-side scroll portion 71 on the motor 5 side, and the second driving-side scroll portion 72 on the discharge opening 3 d side.

The first driving-side scroll portion 71 includes the first driving-side end plate 71 a and the first driving-side walls 71 b.

The first driving-side end plate 71 a is connected to the first driving-side shaft portion 7 c connected to the driving shaft 6, and extends in a direction orthogonal to the driving-side rotation axis CL1. The driving-side shaft portion 7 c is provided so as to be rotatable with respect to the housing 3 through the first driving-side bearing 11 that is a ball bearing.

The first driving-side end plate 71 a has a substantially disc shape in a planar view. The plurality of first driving-side walls 71 b each formed in a spiral shape are provided on the first driving-side end plate 71 a. The first driving-side walls 71 b are disposed at equal intervals around the driving-side rotation axis CL1.

The second driving-side scroll portion 72 includes the second driving-side end plate 72 a and the second driving-side walls 72 b. The plurality of second driving-side walls 72 b each formed in a spiral shape are provided similarly to the above-described first driving-side walls 71 b.

The cylindrical second driving-side shaft portion 72 c that extends in the driving-side rotation axis CL1 is connected to the second driving-side end plate 72 a. The second driving-side shaft portion 72 c is provided so as to be rotatable with respect to the housing 3 through the second driving-side bearing 14 that is a ball bearing. The second driving-side end plate 72 a includes the discharge port 72 d extending along the driving-side rotation axis CL1.

Although not illustrated, a lightened portion (thinned-down portion) for weight reduction is provided on a surface not forming the compression chambers, of each of the first driving-side end plate 71 a and the second driving-side end plate 72 a.

Two seal members 16 are provided on a front end side (left side in FIG. 16) of the second driving-side shaft portion 72 c relative to the second driving-side bearing 14, between the second driving-side shaft portion 72 c and the housing 3. The two seal members 16 and the second driving-side bearing 14 are disposed to include a predetermined interval in the driving side rotation axis CL1. For example, a lubricant that is a grease as a semi-solid lubricant is sealed between the two seal members 16. Note that only one seal member 16 may be provided. In this case, the lubricant is sealed between the seal member 16 and the second driving-side bearing 14.

The first driving-side scroll portion 71 and the second driving-side scroll portion 72 are fixed while the front ends (free ends) of the walls 71 b and 72 b corresponding to each other face each other. The first driving-side scroll portion 71 and the second driving-side scroll portion 72 are fixed by the bolts (wall fixing parts) 31 that are fastened to the flange portions 73 provided at a plurality of positions in the circumferential direction. The flange portions 73 are provided so as to protrude outward in the radial direction.

The driven-side scroll member 90 includes the driven-side end plate 90 a that is located at a substantially center in the axis direction (horizontal direction in figure). The through hole 90 h is provided at a center of the driven-side end plate 90 a, and causes the compressed air to flow toward the discharge port 72 d.

The first driven-side walls 91 b are provided on one side surface of the driven-side end plate 90 a, and the second driven-side walls 92 b are provided on the other side surface of the driven-side end plate 90 a. The first driven-side walls 91 b provided on the motor 5 side from the driven-side end plate 90 a engage with the first driving-side walls 71 b of the first driving-side scroll portion 71. The second driven-side walls 92 b provided on the discharge opening 3 d side from the driven-side end plate 90 a engage with the second driving-side walls 72 b of the second driving-side scroll portion 72.

The driven-side end plate 90 a does not include a lightened portion like the lightened portion provided on each of the driving-side end plates 71 a and 72 a. This is because both surfaces of the driven-side end plate 90 a face the front ends of the driving-side walls 71 b and 72 b to form the compression chambers.

The first support member 33 and the second support member 35 are provided at respective ends of the driven-side scroll member 90 in the axis direction (horizontal direction in figure). The first support member 33 is disposed on the motor 5 side, and the second support member 35 is disposed on the discharge opening 3 d side. The first support member 33 is fixed to the front ends (free ends) of the respective first driven-side walls 91 b on the outer peripheral side by bolts 34, and the second support member 35 is fixed to the front ends (free ends) of the respective second driven-side walls 92 b on the outer peripheral side by bolts 36. The shaft portion 33 a is provided on the center axis side of the first support member 33, and the shaft portion 33 a is fixed to the housing 3 through the first support member bearing 37. The shaft portion 35 a is provided on the center axis side of the second support member 35, and the shaft portion 35 a is fixed to the housing 3 through the second support member bearing 38. As a result, the driven-side scroll member 90 rotates around the driven-side center axis CL2 through the support members 33 and 35.

The pin-ring mechanism (synchronous driving mechanism) 15 is provided between the first support member 33 and the first driving-side end plate 71 a. More specifically, a rolling bearing (ring) is provided on the first driving-side end plate 71 a, and the pin member 15 b is provided on the first support member 33. The pin-ring mechanism 15 transmits the driving force from the driving-side scroll member 70 to the driven-side scroll member 90, and causes the scroll members 70 and 90 to perform rotational movement in the same direction at the same angular velocity.

FIG. 17 illustrates the driving-side scroll member 70. In the driving-side scroll member 70, as described above, the first driving-side scroll portion 71 and the second driving-side scroll portion 72 are fixed by the bolts 31. The first driving-side scroll portion 71 and the second driving-side scroll portion 72 are made of materials having the same linear expansion coefficient, and specifically, are each made of an aluminum alloy. In addition, the bolts 31 are preferably made of the material same as the material of the scroll portions 71 and 72, namely, are preferably made of the aluminum alloy.

Although not illustrated, a lightened portion (thinned-down portion) for weight reduction is provided on a surface not forming the compression chambers, of each of the first driving-side end plate 71 a and the second driving-side end plate 72 a.

FIG. 18 illustrates the driven-side scroll member 90 and the support members 33 and 35. As described above, the driven-side scroll member 90 is fixed to the first support member 33 by the bolts 34, and is fixed to the second support member 35 by the bolts 36. The driven-side scroll member 90 and the support members 33 and 35 are made of materials having the same linear expansion coefficient, and specifically, are each made of a magnesium alloy. In addition, the bolts 34 and 36 are also preferably made of the material same as the material of the driven-side scroll member 90, namely, are preferably made of the magnesium alloy.

The driven-side end plate 90 a does not include a lightened portion like the lightened portion provided on each of the driving-side end plates 71 a and 72 a. This is because both surfaces of the driven-side end plate 90 a face the front ends of the driving-side walls 71 b and 72 b to form the compression chambers.

The co-rotating scroll compressor 1 including the above-described configuration operates in the following manner.

When the driving shaft 6 rotates around the driving-side rotation axis CL1 by the motor 5, the first driving-side shaft portion 7 c connected to the driving shaft 6 also rotates, and the driving-side scroll member 70 accordingly rotates around the driving-side rotation axis CL1. When the driving-side scroll member 70 rotates, the driving force is transmitted from the support members 33 and 35 to the driven-side scroll member 90 through the pin-ring mechanism 15, and the driven-side scroll member 90 rotates around the driven-side rotation axis CL2. At this time, when the pin member 15 b of the pin-ring mechanism 15 moves while being in contact with the inner peripheral surface of the circular hole, the both scroll members 70 and 90 perform rotational movement in the same direction at the same angular velocity.

When the scroll members 70 and 90 perform rotational movement, the air sucked through the air suction opening of the housing 3 is sucked in from outer peripheral side of each of the scroll members 70 and 90, and is taken into the compression chambers formed by the scroll members 70 and 90. Further, compression is separately performed in the compression chambers formed by the first driving-side walls 71 b and the first driven-side walls 91 b and in the compression chambers formed by the second driving-side walls 72 b and the second driven-side walls 92 b. A volume of each of the compression chambers is reduced as each of the compression chambers moves toward the center, which compresses the air. The air compressed by the first driving-side walls 71 b and the first driven-side walls 91 b passes through the through hole 90 h provided in the driven-side end plate 90 a, and is joined with the air compressed by the second driving-side walls 72 b and the second driven-side walls 92 b. The resultant air passes through the discharge port 72 d and is discharged to outside from the discharge opening 3 d of the housing 3. The discharged compressed air is guided to an unillustrated internal combustion engine, and is used as combustion air.

The present embodiment achieves the following action effects.

The first driving-side scroll portion 71 and the second driving-side scroll portion 72 are made of the materials (aluminum alloy) having the same linear expansion coefficient. Therefore, there is no possibility that, in a case where temperature is varied, deformation occurs due to thermal expansion difference to increase stress and to adversely affect compression performance. Further, the first driving-side scroll portion 71 and the second driving-side scroll portion 72 are made of the same material (aluminum alloy). This makes it possible to prevent electrolytic corrosion from being caused by reaction with moisture due to difference in ionization tendency at fixed contact portions.

The driven-side scroll member 90 and the support members 33 and 35 are made of the materials (magnesium alloy) having the same linear expansion coefficient. Therefore, there is no possibility that, in a case where temperature is varied, deformation occurs due to thermal expansion difference to increase stress and to adversely affect compression performance. Further, the driven-side scroll member 90 and the support members 33 and 35 are made of the same material (magnesium alloy). This makes it possible to prevent electrolytic corrosion from being caused by reaction with moisture due to difference in ionization tendency at fixed contact portions.

Further, the driven-side scroll member 90 is made of a magnesium alloy that is lower in specific gravity than the aluminum alloy of the driving-side scroll member 70. As a result, the weight reduction becomes possible even in the driven-side scroll member 90 including the driven-side end plate 90 a that cannot be reduced in weight unlike the driving-side end plates 71 a and 72 a. Accordingly, it is possible to reduce rotational inertial force.

Note that, in the present embodiment, the magnesium alloy is used for the driven-side scroll member 90 and the support members 33 and 35. Alternatively, an aluminum alloy may be used.

Ninth Embodiment

A ninth embodiment of the present invention is described below. A schematic configuration of a co-rotating scroll compressor according to the present embodiment is substantially similar to that in the eighth embodiment described with reference to FIG. 16. Accordingly, description of the schematic configuration is omitted.

FIG. 19 is a plan view of the driven-side scroll member 90. The driven-side scroll member 90 includes three lines of driven-side walls 91 b (92 b). A plurality of circular through holes 90 a 1 are provided on the driven-side end plate 90 a in the vicinity of an outer peripheral end 91 e of each of the driven-side walls 91 b. More specifically, in a case where a position of the outer peripheral end 91 e that is an winding end of each of the driven-side walls 91 b is regarded as 0 degrees, the through holes 90 a 1 are provided in a range of 0 degrees to −120 degrees from a center of each of the spiral driven-side walls 91 b, preferably in a range of 0 degrees to −90 degrees, and more preferably in a range of 0 degrees to −45 degrees. Note that a negative angle indicates center side (inner peripheral side) of each of the driven-side walls 91 b. A shape of each of the through holes 90 a 1 may be other shapes such as an elliptical shape and an oval shape, in place of a circular shape, and the number of through holes 90 a 1 may be one.

Further, the through holes 90 a 1 are provided in the vicinity of a ventral side 91 f of each of the driven-side walls 91 b, namely, are brought close to the ventral side 91 f rather than a dorsal side 91 g opposite to the ventral side 91 f of each of the driven-side walls 91 b. Accordingly, the through holes 90 a 1 are located on the outer peripheral side as close as possible.

A notch 90 a 2 is provided on the driven-side end plate 90 a on the outer peripheral side (counterclockwise direction in FIG. 19) of the outer peripheral end 91 e of each of the driven-side walls 91 b. In other words, the driven-side end plate 90 a is lacked on the outer peripheral side of each of the outer peripheral end 91 e.

FIG. 20 illustrates a state where the driven-side scroll member 90 and the driving-side scroll member 70 engage with each other. FIG. 21 is a cross-sectional view as viewed from arrow B in FIG. 20. As can be seen from FIG. 21, the notch 90 a 2 makes the compression chambers S1 on the respective sides of the driven-side end plate 90 a communicate with each other. Note that, in a region where the notch 90 a 2 is provided, the driving-side walls 71 b and 72 b are made large by a dimension corresponding to a thickness of the driven-side end plate 90 a such that the front ends of the driven-side walls 71 b and 72 corresponding to each other are substantially butted to each other.

In contrast, in a case where the notch a2 is not provided, the driven-side scroll member 90 and the driving-side scroll member 70 engage with each other as illustrated in FIG. 22. FIG. 23 is a cross-sectional view as viewed from arrow C in FIG. 22. As can be seen from FIG. 23, in the case where the driven-side end plate 90 a is provided on the outer peripheral side of the outer peripheral end 91 e of each of the driven-side walls 91 b, the compression chambers S1 and S1 are formed on the respective sides of the driven-side end plate 90 a, and are independent from each other.

Note that, as can be seen from comparison between FIG. 23 and FIG. 21, the compression chambers S1 illustrated in FIG. 21 according to the present embodiment can be increased by a volume amount corresponding to the thickness of each of the driven-side walls 91 b. This makes it possible to increase a compression ratio.

The co-rotating scroll compressor 1 including the above-described configuration operates in the following manner.

When the driving shaft 6 rotates around the driving-side rotation axis CL1 by the motor 5, the first driving-side shaft portion 7 c connected to the driving shaft 6 also rotates, and the driving-side scroll member 70 accordingly rotates around the driving-side rotation axis CL1. When the driving-side scroll member 70 rotates, the driving force is transmitted from the support members 33 and 35 to the driven-side scroll member 90 through the pin-ring mechanism 15, and the driven-side scroll member 90 rotates around the driven-side rotation axis CL2. At this time, when the pin member 15 b of the pin-ring mechanism 15 moves while being in contact with the inner peripheral surface of the circular hole, the both scroll members 70 and 90 perform rotational movement in the same direction at the same angular velocity.

When the scroll members 70 and 90 perform rotational movement, the air sucked through the air suction opening of the housing 3 is sucked in from outer peripheral side of each of the scroll members 70 and 90, and is taken into the compression chambers formed by the scroll members 70 and 90. Further, compression is separately performed in the compression chambers formed by the first driving-side walls 71 b and the first driven-side walls 91 b and in the compression chambers formed by the second driving-side walls 72 b and the second driven-side walls 92 b. A volume of each of the compression chambers is reduced as each of the compression chambers moves toward the center, which compresses the air. The air compressed by the first driving-side walls 71 b and the first driven-side walls 91 b passes through the discharge through hole 90 h provided in the driven-side end plate 90 a, and is joined with the air compressed by the second driving-side walls 72 b and the second driven-side walls 92 b. The resultant air passes through the discharge port 72 d and is discharged to outside from the discharge opening 3 d of the housing 3. The discharged compressed air is guided to an unillustrated internal combustion engine, and is used as combustion air.

The present embodiment achieves the following action effects.

The through holes 90 a 1 and the notch 90 a 2 are provided in the vicinity of the outer peripheral end 91 e of each of the driven-side walls 91 b, on the driven-side end plate 90 a. As a result, the compression chambers S1 formed on the respective sides of the driven-side end plate 90 a communicate with each other to equalize the pressure. This makes it possible to reduce the possibility of inhibiting discharge when the compression chambers on both sides are joined at the discharge through hole 90 h (see FIG. 1) before discharge of the air.

Further, it is possible to reduce the possibility of application of a thrust load on the scroll members 70 and 90 due to the pressure difference between the compression chambers S1 on both sides.

The through holes 90 a 1 or the notch 90 a 2 are provided in the vicinity of the outer peripheral end 91 e of each of the driven-side walls 91 b to reduce the weight on the outer peripheral side of the driven-side scroll member 90. This makes it possible to reduce rotational inertial force of the driven-side scroll member 90. In particular, the both surfaces of the driven-side end plate 90 a face the respective compression chambers, and accordingly, the driven-side end plate 90 a cannot be lightened unlike the driving-side end plates 71 a and 72 a. Therefore, the weight reduction by the through holes 90 a 1 and the notch 90 a 2 is effective.

The through holes 90 a 1 and the notch 90 a 2 are positioned in the vicinity of the outer peripheral end 91 e of each of the driven-side walls 91 b. As a result, the pressure is equalized before the pressure is increased to a predetermined value or more, which makes it possible to reduce recompression.

Providing the through holes 90 a 1 at the positions close to the ventral side 91 f of each of the driven-side walls 91 b makes it possible to locate the through holes 90 a 1 on the outer peripheral side as close as possible. This makes it possible to further reduce the rotational inertial force of the driven-side scroll member 90.

Note that, the structure in the above-described embodiment includes both of the through holes 90 a 1 and the notch 90 a 2; however, any one of them may be adopted.

Further, as illustrated in FIG. 24, even in a case where the driven-side end plate 90 a is extended on the outer peripheral side of the outer peripheral end 91 e without providing the notch 90 a 2 illustrated in FIG. 19, the through holes 90 a 1 may be provided in the extended region.

Tenth Embodiment

A tenth embodiment of the present invention is described below. A schematic configuration of a co-rotating scroll compressor according to the present embodiment is substantially similar to that in the eighth embodiment described with reference to FIG. 16. Accordingly, description of the schematic configuration is omitted.

<Surface Treatment>

As a base material of each of the driving-side scroll member 70 and the driven-side scroll member 90, a metal is used. More specifically, an aluminum alloy, a magnesium alloy, or an iron-based material is used. When the same kind of materials are used for the driving-side scroll member 70 and the driven-side scroll member 90, seizure may occur at a sliding portion. Therefore, surface treatment is performed. For example, electroless nickel-phosphorous (Ni—P) plating is used as the surface treatment.

The driving-side scroll member 70 is not subjected to the surface treatment. In other words, the metal of the base material is exposed on a surface of the driving-side scroll member 70.

In contrast, the driven-side scroll member 90 is subjected to the surface treatment. More specifically, the surface treatment is performed on at least a region of the driven-side scroll member 90 coming into contact with the driving-side scroll member 70. In the first driven-side walls 91 b and/or the second driven-side walls 92 b, however, the surface treatment is not performed on the outer peripheral side in a range from the winding end of each of the first driven-side walls 91 b and/or the second driven-side walls 92 b to an angle that is obtained by dividing π (rad) by the number of the first driven-side walls 91 b or the number of the second driven-side walls 92 b. In the present embodiment, the number of lines of each of the driven-side walls 91 b and 92 b is set to two, the surface treatment is not performed on the outer peripheral side in a range from each winding end to π/2 (=90 degrees). More specifically, as illustrated in FIG. 25, the surface treatment is not performed in a range (range illustrated by thick line) from the winding end of each of the driven-side walls 91 b (92 b) to 90 degrees. In this angle range, the outer peripheral surface (dorsal side surface) of each of the driven-side walls 91 b (92 b) does not come into contact with the corresponding driving-side wall 71 b (72 b).

At the time of performing the surface treatment, a region in the above-described angle range (winding end of each of driven-side walls 91 b and 92 b to 90 degrees) is held by a tool to fix the driven-side scroll member 90 to a fixed position. The treatment such as electroless plating is performed in this state.

The co-rotating scroll compressor 1 including the above-described configuration operates in the following manner.

When the driving shaft 6 rotates around the driving-side rotation axis CL1 by the motor 5, the first driving-side shaft portion 7 c connected to the driving shaft 6 also rotates, and the driving-side scroll member 70 accordingly rotates around the driving-side rotation axis CL1. When the driving-side scroll member 70 rotates, the driving force is transmitted from the support members 33 and 35 to the driven-side scroll member 90 through the pin-ring mechanism 15, and the driven-side scroll member 90 rotates around the driven-side rotation axis CL2. At this time, when the pin member 15 b of the pin-ring mechanism 15 moves while being in contact with the inner peripheral surface of the circular hole, the scroll members 70 and 90 perform rotational movement in the same direction at the same angular velocity.

When the scroll members 70 and 90 perform rotational movement, the air sucked through the air suction opening of the housing 3 is sucked in from outer peripheral side of each of the scroll members 70 and 90, and is taken into the compression chambers formed by the scroll members 70 and 90. Further, compression is separately performed in the compression chambers formed by the first driving-side walls 71 b and the first driven-side walls 91 b and in the compression chambers formed by the second driving-side walls 72 b and the second driven-side walls 92 b. A volume of each of the compression chambers is reduced as each of the compression chambers moves toward the center, which compresses the air. The air compressed by the first driving-side walls 71 b and the first driven-side walls 91 b passes through the discharge through hole 90 h provided in the driven-side end plate 90 a, and is joined with the air compressed by the second driving-side walls 72 b and the second driven-side walls 92 b. The resultant air passes through the discharge port 72 d and is discharged to outside from the discharge opening 3 d of the housing 3. The discharged compressed air is guided to an unillustrated internal combustion engine, and is used as combustion air.

The present embodiment achieves the following action effects.

The surface treatment is not performed on the driving-side scroll member 70, but is performed on at least the region of the driven-side scroll member 90 coming into contact with the driving-side scroll member 70. As a result, even if the same kind of metal materials are used as the base material of the driving-side scroll member 70 and the base material of the driven-side scroll member 90, it is possible to prevent seizure. In addition, it is sufficient to perform the surface treatment on one driven-side scroll member 90 without performing the surface treatment on both of the first driving-side scroll portion 71 and the second driving-side scroll portion 72. This makes it possible to reduce the cost. Accordingly, it is possible to reduce the cost while maintaining durability of the scroll members.

If the surface treatment is performed on both of the first driving-side scroll portion 71 and the second driving-side scroll portion 72, films formed by the surface treatment on the respective scroll portions may be different in thickness from each other. If the film thicknesses are different from each other, clearances (tip clearances) between the driving-side end plate 71 a (72 a) and the front ends of the driven-side walls 91 b and 92 b are different from one another, which may adversely affect compression performance. In contrast, when the surface treatment is performed on one driven-side scroll member 90, the surface treatment is performed under the same condition. This makes it possible to make the film thicknesses on both surfaces of the driven-side end plate 90 a equivalent to each other, and to accordingly manage the tip clearances with high accuracy.

In the range from the winding end of each of the driven-side walls 91 b (92 b) to the angle obtained by dividing n (rad) by the number of walls provided on one surface of the end plate, the outer peripheral side (dorsal side) of each of the driven-side walls 91 b (92 b) does not come into contact with the corresponding driving-side wall 71 b (72 b). Accordingly, it is unnecessary to perform the surface treatment on the angle range, and a tool can be fixed to the angle range in the surface treatment. More specifically, in the surface treatment, the tool is fixed to the angle range to support the driven-side scroll member 90. As a result, the surface treatment is performable while the driven-side scroll member 90 is stably supported. Note that the range where the surface treatment is not performed is not necessarily provided over the entire angle range described above, and it is sufficient to provide a region where the tool is fixed, as a surface-untreated region.

Note that, in place of the above-described angle range, or together with the angle range, the region where the surface treatment is not performed may be the inner peripheral surface of the discharge through hole 90 h. The driving-side walls 71 b (72 b) do not come into contact with the inner peripheral surface of the discharge through hole 90 h. Accordingly, it is unnecessary to perform the surface treatment on the inner peripheral surface of the discharge through hole 90 h, and a tool can be fixed to the inner peripheral surface of the discharge through hole 90 h in the surface treatment. More specifically, in the surface treatment, a rod-like tool is inserted into the discharge through hole 90 h, and is pressed against and fixed to the inner peripheral surface of the discharge through hole 90 h to support the driven-side scroll member 90. As a result, the surface treatment is performable while the driven-side scroll member 90 is stably supported. Note that the range where the surface treatment is not performed is not necessarily provided over the entire inner peripheral surface of the discharge through hole 90 h, and it is sufficient to provide a region where the tool is fixed, as the surface-untreated region.

Note that, in the above-described embodiments, the co-rotating scroll compressor is used as the supercharger; however, the present invention is not limited thereto. The co-rotating scroll compressor is widely used to compress fluid, and for example, can be used as a refrigerant compressor used in air conditioner. In addition, the scroll compressor 1 according to the present invention is applicable to an air brake device using air force, as a brake system for a railway vehicle.

REFERENCE SIGNS LIST

-   1, 1A, 1B, 1C Co-rotating scroll compressor -   3 Housing -   3 a Motor accommodation portion (first housing) -   3 b Scroll accommodation portion (second housing) -   3 c Cooling fin -   3 d Discharge opening -   5 Motor (driving unit) -   5 a Stator -   5 b Rotor -   6 Driving shaft -   11 First driving-side bearing -   14 Second driving-side bearing -   14 a Preload member -   15 Pin-ring mechanism (synchronous driving mechanism) -   15 a Ring member -   15 b Pin member -   17 Rear-end bearing -   30 Flange portion (fastening portion) -   31 Bolt (wall fixing part) -   32 Bolt -   33 First support member -   33 a First support member shaft portion -   35 Second support member -   35 a Second support member shaft portion -   37 First support member bearing (first driven-side bearing) -   38 Second support member bearing (second driven-side bearing) -   70 Driving-side scroll member -   71 First driving-side scroll portion -   71 a First driving-side end plate -   71 b First driving-side wall -   71 b 1 Key groove -   72 Second driving-side scroll portion -   72 a Second driving-side end plate -   72 b Second driving-side wall -   72 c Second driving-side shaft portion -   72 d Discharge port -   72 e Winding end part -   73 Flange portion -   74 Key member -   90 Driven-side scroll member -   90 a Driven-side end plate -   90 h Through hole -   91 b First driven-side wall -   92 b Second driven-side wall -   CL1 Driving-side rotation axis -   CL2 Driven-side rotation axis -   P Division surface -   S1 Compression chamber 

1. A co-rotating scroll compressor, comprising: a driving-side scroll member that is rotationally driven by a driving unit and includes a spiral driving-side wall disposed on a driving-side end plate; a driven-side scroll member that includes a spiral driven-side wall corresponding to the driving-side wall, the driven-side wall being disposed on a driven-side end plate and engaging with the driving-side wall to form a compression space; and a synchronous driving mechanism that transmits driving force from the driving-side scroll member to the driven-side scroll member to cause the driving-side scroll member and the driven-side scroll member to perform rotational movement in a same direction at a same angular velocity, wherein the driving-side scroll member includes a first driving-side scroll portion, a second driving-side scroll portion, and a wall fixing part, the first driving-side scroll portion including a first driving-side end plate and a first driving-side wall and being driven by the driving unit, the second driving-side scroll portion including a second driving-side end plate and a second driving-side wall, and the wall fixing part performing fixing while a front end in a rotation axis direction of the first driving-side wall and a front end in the rotation axis direction of the second driving-side wall face each other, and the driven-side scroll member includes a first driven-side wall and a second driven-side wall, the first driven-side wall being provided on one side surface of the driven-side end plate and engaging with the first driving-side wall, and the second driven-side wall being provided on another side surface of the driven-side end plate and engaging with the second driving-side wall.
 2. The co-rotating scroll compressor according to claim 1, wherein the wall fixing part includes a key groove provided on each of the front end of the first driving-side wall and the front end of the second driving-side wall, and a key member to be inserted into the key grooves.
 3. The co-rotating scroll compressor according to claim 1, wherein the wall fixing part includes a groove provided on one of the front end of the first driving-side wall and the front end of the second driving-side wall, and a protrusion that is provided on the other of the front end of the second driving-side wall and the front end of the first driving-side wall and is to be inserted into the groove.
 4. The co-rotating scroll compressor according to claim 1, wherein the driven-side scroll member includes a first driven-side scroll portion and a second driven-side scroll portion, the first driven-side scroll portion including a first driven-side end plate and a first driven-side wall that is provided on one side surface of the first driven-side end plate and engages with the first driving-side wall, the second driven-side scroll portion including a second driven-side end plate and a second driven-side wall that is provided on one side surface of the second driven-side end plate and engages with the second driving-side wall, and the first driven-side end plate and the second driven-side end plate are fixed while another side surface of the first driven-side end plate and another side surface of the second driven-side end plate are superimposed.
 5. The co-rotating scroll compressor according to claim 1, wherein timing when fluid is compressed and discharged by the first driving-side scroll portion and timing when fluid is compressed and discharged by the second driving-side scroll portion are different from each other.
 6. The co-rotating scroll compressor according to claim 1, wherein the second driving-side scroll portion includes a discharge port through which fluid compressed by the first driving-side scroll portion as well as fluid compressed by the second driving-side scroll portion are discharged, and discharge pressure of the fluid compressed by the first driving-side scroll portion is set higher than discharge pressure of the fluid compressed by the second driving-side scroll portion.
 7. The co-rotating scroll compressor according to claim 1, wherein the first driving-side wall has a wall height larger than a wall height of the second driving-side wall.
 8. The co-rotating scroll compressor according to claim 1, wherein the second driving-side scroll portion includes a discharge port through which fluid compressed by the first driving-side scroll portion as well as fluid compressed by the second driving-side scroll portion are discharged, and the first driving-side wall has a wall height lower than a wall height of the second driving-side wall.
 9. The co-rotating scroll compressor according to claim 1, further comprising: a first support member that is fixed to a front end side in the axis direction of the first driven-side wall and rotates together with the first driven-side wall, the first driving-side end plate being disposed in between the first support member and the first driven-side wall; and a second support member that is fixed to a front end side in the axis direction of the second driven-side wall and rotates together with the second driven-side wall, the second driving-side end plate being disposed in between the second support member and the second driven-side wall, wherein the first driving-side scroll portion and the second driving-side scroll portion are made of materials having a same linear expansion coefficient, and/or the driven-side scroll member, the first support member, and the second support member are made of materials having a same linear expansion coefficient.
 10. The co-rotating scroll compressor according to claim 9, wherein the material used for the driven-side scroll member is lower in specific gravity than the materials used for the first driving-side scroll portion and the second driving-side scroll portion.
 11. The co-rotating scroll compressor according to claim 1, wherein the driven-side end plate includes a through hole or a notch in a vicinity of an outer peripheral end of the driven-side wall.
 12. The co-rotating scroll compressor according to claim 11, wherein the through hole is provided at a position close to a ventral side of the driven-side wall.
 13. The co-rotating scroll compressor according to claim 1, wherein the driving-side scroll member is not subjected to surface treatment, and at least a region of the driven-side scroll member coming into contact with the driving-side scroll member is subjected to the surface treatment.
 14. The co-rotating scroll compressor according to claim 13, wherein a plurality of the driving-side walls are provided at predetermined angular intervals around a center of the driving-side end plate, the driven-side walls in a number corresponding to the number of driving-side walls are provided at predetermined angular intervals around a center of the driven-side end plate, and in the first driven-side walls and/or the second driven-side walls, the surface treatment is not performed on an outer peripheral side in a range from a winding end of each of the first driven-side walls and/or the second driven-side walls to an angle that is obtained by dividing π (rad) by the number of the first driven-side walls or the number of the second driven-side walls.
 15. The co-rotating scroll compressor according to claim 13, wherein a through hole is provided at a center of the driven-side end plate, and the surface treatment is not performed on an inner peripheral surface forming the through hole. 